Mitt Romney is the favorite to receive Sen. Jim DeMint's (R-S.C.) much-sought-after endorsement in the race for the Republican presidential nomination, according to knowledgeable GOP sources.

DeMint, who endorsed the former Massachusetts governor in 2008, made clear in an interview late last week that he has made no decisions on whom he will support in the 2012 primary. But Republican operatives familiar with the DeMint-Romney relationship and privy to the conservative Senator's private assessment of the GOP field believe Romney is the most likely candidate to receive the backing of the tea party favorite.

"Jim is far more likely to endorse Mitt than anyone else currently in the race," a Republican with South Carolina ties said. "Jim is a business guy and that's his background. He's not really the good ol' boy conservative type. So Mitt in a lot of ways is a more comfortable fit for him."

"Jim actually likes Romney," added a GOP operative based in the Palmetto State. "I think, politically, he had some doubts about his ability to engage conservatives, but it would not surprise me for Jim to endorse Romney at some point."

In the past few years, DeMint has become somewhat of a national hero among conservative activists. His Senate Conservatives Fund political action committee raised more than $9 million last cycle, much of it spent to help elect tea-party-inspired stalwarts such as GOP Sens. Ron Johnson (Wis.), Rand Paul (Ky.) and Marco Rubio (Fla.). In some instances, DeMint waded into Senate primaries to oppose candidates supported by Senate Republican leaders, much to the delight of the tea party.

This anti-establishment image, and DeMint's popularity among South Carolina Republicans, has elevated the value of his support in a key presidential primary state beyond what it was in 2008. This cycle, DeMint decided not to offer an early endorsement, loosely forming the "keep your powder dry caucus" with an inner circle of supporters as a way to increase South Carolina's importance in the nominating contest and raise the impact of his endorsement.

DeMint told Roll Call on Thursday that he and Romney occasionally trade emails, but he said they haven't talked in some time. South Carolina's junior Senator said he thinks highly of many of the candidates in the race and that the Palmetto State primary remains wide open. That primary is set for Jan. 21, presumably giving DeMint another three months to make his decision.

Asked specifically to comment on Romney's performance thus far, DeMint said: "He's doing really well; he looks like the steady hand in the race. I think he's done well in the debates."

"You can find really good things about all of the candidates. But I'm real comfortable just waiting because there's still a lot to be determined," DeMint added. "I don't pretend to have that much sway. ... I've found endorsements are only important until you make it. After that, people say: 'I don't agree with that.'"

Romney is viewed in some quarters as less conservative than other Republican presidential candidates. The former Bay State governor took some moderate positions on social issues when running for office there, although he later disavowed most of them during his 2008 presidential bid. Romney's Massachusetts health care plan has been widely panned by Republicans for its mandate to purchase insurance and for its other similarities to the law President Barack Obama signed in 2010.

But even if their politics haven't always been perfectly aligned, DeMint and Romney have much in common. Both came to politics from the business world — Romney from the private investment and management firm Bain Capital, which he helped launch, and DeMint from an advertising and marketing company he founded and operated. Their political advisers have also been intertwined: Romney's 2008 state director Terry Sullivan — who currently serves as Rubio's deputy chief of staff — was DeMint's 2004 campaign manager.

Despite conservative and tea party angst over Romney, these commonalities and the inability of anyone — thus far —to knock Romney out of contention could facilitate another DeMint endorsement. That the two men seem to genuinely like each other and have stayed in touch since the 2008 race is viewed as an asset for Romney, who could use the seal of approval of a conservative like DeMint to bolster his standing with the GOP's conservative flank.

"Gov. Romney has a great deal of respect for Sen. DeMint and his efforts to return fiscal sanity to Washington. He considers the Senator a friend and a leader in the conservative movement," Romney campaign spokesman Ryan Williams said.

South Carolina Republicans, including DeMint and Sen. Lindsey Graham, say the state's primary is fluid and within reach for almost any of the candidates. An American Research Group survey of South Carolina GOP primary voters released last week showed Georgia businessman Herman Cain in front with 26 percent, followed closely by Romney with 25 percent. Texas Gov. Rick Perry had 15 percent and 12 percent were undecided. The lead previously belonged to Perry.

As DeMint considers whom to endorse — or whether to endorse at all — he said he wants to hear more from all of the candidates regarding their views on the Congressional appropriations process, the super committee and what Washington should do to balance the federal budget. The Senator said candidates have not been specific enough on those issues. "They have not been real out front," he said.

DeMint is "real impressed" with Cain, calling him a "business guy" with a plan that "he's sticking to, and I think that's good." DeMint noted his relationships with former Speaker Newt Gingrich (Ga.), Rep. Michele Bachmann (Minn.) and former Sen. Rick Santorum (Pa.), whom he called one of his best friends. Perry is the only top candidate DeMint has not met in person, although they've spoken by phone. The Senator said he would reserve judgment on the Texas governor.

But many Republicans still expect DeMint to settle on Romney, as long as the candidate doesn't fade from the race or appear too uncompetitive in South Carolina. "He likes to talk about Romney as the last man standing," said one Republican lobbyist with relationships in the Senate.